In order to further increase material utilization rate and reduce complexity of manufacturing process, the ink jet printing technology has been applied to the manufacturing process for flat panel display at present. For example, the ink-jet printing technology can be applied to the flexible OLED (Organic Light Emitting Diode) film packaging process for uniformly depositing an organic material on an OLED light-emitting device by means of ink-jetting.
The basic operating principle of ink-jet printing can be summarized as follows: ink droplets are generated first, then tiny ink droplets are guided to a preset position by a nozzle, the smaller the droplet, the more precise the position of dropping, and the higher the printing resolution. Ink-jet printing has very high requirements on ink jetting amount and precision of ink jetting position, so an ink-jet printhead is usually formed by many tiny micro-nozzles, and generally each nozzle has a dropping amount of less than 100 picoliter (pL). During the process of ejecting ink, sporadic droplets might be sputtered beyond the preset positions for the droplets, which may be referred to as bad satellite, and the sputtered sporadic droplets may be referred to as satellite droplets. When the ink-jet printing process is implemented in the middle of the printing area of an object to be printed (i.e. a substrate), the sputtered satellite droplets may still drop on the printing area, but when the ink-jet printing process is implemented at edges of the printing area of an object to be printed, the sputtered satellite droplets may drop on areas outside of the printing area of the object to be printed. The satellite droplets on areas outside of the printing area will have bad effects on subsequent manufacturing processes, for example, causing inorganic sedimentary fault in the subsequent chemical vapor deposition process, causing laminated bubbles in the subsequent membrane pasting process, etc., which will influence the final product quality.
In summary, in the manufacturing process for flat panel display, when printing the object to be printed by means of the ink-jet printing technology, satellite droplets dropping on areas outside of the printing area will have undesirable effects on subsequent manufacturing processes and thus influencing the final product quality.